Merge remote-tracking branch 'origin/main' into fix_incisionEdgeBorders

.github/workflows/ci.yml

@@ -14,31 +14,13 @@ jobs:
         sofa_branch: [master]
 
     steps:
-      - name: (Mac) Workaround for homebrew
-        shell: bash
-        if: runner.os == 'macOS'
-        run: |
-            rm -f /usr/local/bin/2to3
-            rm -f /usr/local/bin/idle3
-            rm -f /usr/local/bin/pydoc3
-            rm -f /usr/local/bin/python3
-            rm -f /usr/local/bin/python3-config
-            rm -f /usr/local/bin/2to3-3.11
-            rm -f /usr/local/bin/idle3.11
-            rm -f /usr/local/bin/pydoc3.11
-            rm -f /usr/local/bin/python3.11
-            rm -f /usr/local/bin/python3.11-config
-            rm -f /usr/local/bin/go
-            rm -f /usr/local/bin/gofmt
-            
       - name: Setup SOFA and environment
         id: sofa
         uses: sofa-framework/sofa-setup-action@v5
         with:
           sofa_root: ${{ github.workspace }}/sofa
           sofa_version: ${{ matrix.sofa_branch }}
           sofa_scope: 'standard'
-
       - name: Checkout source code
         uses: actions/checkout@v2
         with:
@@ -56,7 +38,7 @@ jobs:
                   -DCMAKE_BUILD_TYPE=Release \
                   -DCMAKE_INSTALL_PREFIX="$WORKSPACE_INSTALL_PATH" \
                   ../src \
-              && ninja -v install"
+              && ninja install"
           else
             cd "$WORKSPACE_BUILD_PATH"
             ccache -z
@@ -68,7 +50,7 @@ jobs:
               -DCMAKE_BUILD_TYPE=Release \
               -DCMAKE_INSTALL_PREFIX="$WORKSPACE_INSTALL_PATH" \
               ../src
-            ninja -v install
+            ninja install
             echo ${CCACHE_BASEDIR}
             ccache -s
           fi
@@ -83,25 +65,26 @@ jobs:
         with:
           name: Tearing_${{ steps.sofa.outputs.run_branch }}_for-SOFA-${{ steps.sofa.outputs.sofa_version }}_${{ runner.os }}
           path: ${{ env.WORKSPACE_ARTIFACT_PATH }}
-
+      
       - name: Set env vars for tests
         shell: bash
         run: |
           # Set env vars for tests
           if [[ "$RUNNER_OS" == "Windows" ]]; then
             echo "$WORKSPACE_ARTIFACT_PATH/lib" >> $GITHUB_PATH
             echo "$WORKSPACE_ARTIFACT_PATH/bin" >> $GITHUB_PATH
+            echo "$SOFA_ROOT/plugins/SofaPython3/bin" >> $GITHUB_PATH
             echo "SOFA_PLUGIN_PATH=$WORKSPACE_ARTIFACT_PATH/bin" | tee -a $GITHUB_ENV
           else
             echo "SOFA_PLUGIN_PATH=$WORKSPACE_ARTIFACT_PATH/lib" | tee -a $GITHUB_ENV
           fi
 
           if [[ "$RUNNER_OS" == "macOS" ]]; then
-            echo "DYLD_LIBRARY_PATH=$WORKSPACE_ARTIFACT_PATH/lib:$SOFA_ROOT/lib:$DYLD_LIBRARY_PATH" | tee -a $GITHUB_ENV
+            echo "DYLD_LIBRARY_PATH=$WORKSPACE_ARTIFACT_PATH/lib:$SOFA_ROOT/lib:$SOFA_ROOT/plugins/SofaPython3/lib:$DYLD_LIBRARY_PATH" | tee -a $GITHUB_ENV
           fi
 
           if [[ "$RUNNER_OS" == "Linux" ]]; then
-            echo "LD_LIBRARY_PATH=$WORKSPACE_ARTIFACT_PATH/lib:$SOFA_ROOT/lib:$LD_LIBRARY_PATH" | tee -a $GITHUB_ENV
+            echo "LD_LIBRARY_PATH=$WORKSPACE_ARTIFACT_PATH/lib:$SOFA_ROOT/lib:$SOFA_ROOT/plugins/SofaPython3/lib:$LD_LIBRARY_PATH" | tee -a $GITHUB_ENV
           fi
 
       - name: Run Tearing_test
@@ -111,6 +94,28 @@ jobs:
           chmod +x $WORKSPACE_BUILD_PATH/bin/Tearing_test${{ steps.sofa.outputs.exe }}
           cd $WORKSPACE_BUILD_PATH
           ./bin/Tearing_test${{ steps.sofa.outputs.exe }}
+          
+      - name: Fetch, install and run Regression_test
+        if: always()
+        shell: bash
+        run: |
+          if [[ "$RUNNER_OS" != "macOS" ]]; then
+            # Get regression from github releases
+            mkdir -p "${{ runner.temp }}/regression_tmp/install"
+            curl --output "${{ runner.temp }}/regression_tmp/${RUNNER_OS}.zip" -L https://github.com/sofa-framework/regression/releases/download/release-master/Regression_test_master_for-SOFA-${{ steps.sofa.outputs.sofa_version }}_${RUNNER_OS}.zip
+            unzip -qq "${{ runner.temp }}/regression_tmp/${RUNNER_OS}.zip" -d "${{ runner.temp }}/regression_tmp/install"
+            # Install it in the SOFA bin directory
+            $SUDO mv "${{ runner.temp }}"/regression_tmp/install/Regression_*/bin/* "${SOFA_ROOT}/bin"
+            chmod +x ${SOFA_ROOT}/bin/Regression_test${{ steps.sofa.outputs.exe }}
+            # Setup mandatory env vars
+            export REGRESSION_SCENES_DIR="${WORKSPACE_SRC_PATH}/scenes"
+            export REGRESSION_REFERENCES_DIR="${WORKSPACE_SRC_PATH}/regression/references"
+            # Run regression test bench
+            ${SOFA_ROOT}/bin/Regression_test${{ steps.sofa.outputs.exe }}
+          else
+            echo "Regression tests are not supported on the CI for macOS yet (TODO)"
+          fi
+
 
   deploy:
     name: Deploy artifacts

CMakeLists.txt

@@ -18,14 +18,22 @@ set(HEADER_FILES
     ${TEARING_SRC_DIR}/TearingAlgorithms.h
     ${TEARING_SRC_DIR}/TearingAlgorithms.inl
 
+    ${TEARING_SRC_DIR}/BaseTearingEngine.h
+    ${TEARING_SRC_DIR}/BaseTearingEngine.inl
+
     ${TEARING_SRC_DIR}/TearingEngine.h
     ${TEARING_SRC_DIR}/TearingEngine.inl
+
+    ${TEARING_SRC_DIR}/TearingScenarioEngine.h
+    ${TEARING_SRC_DIR}/TearingScenarioEngine.inl
 )
 
 set(SOURCE_FILES
     ${TEARING_SRC_DIR}/initTearing.cpp
     ${TEARING_SRC_DIR}/TearingAlgorithms.cpp
+    ${TEARING_SRC_DIR}/BaseTearingEngine.cpp
     ${TEARING_SRC_DIR}/TearingEngine.cpp
+    ${TEARING_SRC_DIR}/TearingScenarioEngine.cpp
 )
 
 set(README_FILES

Tearing_test/TearingEngine_test.cpp

@@ -151,9 +151,9 @@ struct TearingEngine_Case1 : public TearingEngine_test
             m_instance.simulate(0.05);
         }
 
-        EXPECT_EQ(topoCon->getNbTriangles(), 1450);
-        EXPECT_EQ(topoCon->getNbEdges(), 2223);
-        EXPECT_EQ(topoCon->getNbPoints(), 774);
+        EXPECT_EQ(topoCon->getNbTriangles(), 1505);
+        EXPECT_EQ(topoCon->getNbEdges(), 2334);
+        EXPECT_EQ(topoCon->getNbPoints(), 830);
 
         return true;
     }

regression/regression_tests.py

@@ -0,0 +1,30 @@
+import os
+import sys
+
+#arguments:
+# 0 - script name
+# 1 - sofa build dir
+#use: 
+# python regression_tests.py /c/projects/sofa-build/
+
+sofa_build_dir = sys.argv[1]
+pwd = os.getcwd()
+reg_binary = sofa_build_dir + '/bin/Release/Regression_test.exe'
+ref_dir = pwd + "/references/"
+scenes_dir = pwd + "/../scenes/"
+
+# logs
+print("--- Regression config ---")
+print("sofa_build_dir: " + sofa_build_dir)
+print("ref_dir: " + ref_dir)
+print("scenes_dir: " + scenes_dir)
+print("reg_binary: " + reg_binary)
+print("-------------------------")
+
+os.environ["REGRESSION_SCENES_DIR"] = scenes_dir
+os.environ["REGRESSION_REFERENCES_DIR"] = ref_dir
+
+os.environ["SOFA_ROOT"] = sofa_build_dir
+os.environ["SOFA_PLUGIN_PATH"] = sofa_build_dir + '/lib'
+
+os.system(reg_binary)

scenes/Benchmarks/Scenario-01_squareTissue_horizontal-cut.scn

@@ -53,14 +53,14 @@
 
         <BoxROI template="Vec3d" name="PulledSide" box="-0.1 0.1 0.1  10.1 -0.1 -0.1" drawBoxes="1"/>
         <ConstantForceField name="CFF" indices="@PulledSide.indices" forces="0 -100 0" showArrowSize=".01" />
-
-        <TearingEngine name="TearingEngine" input_position="@Mo.position" showTearableTriangle="0" showFracturePath="0"
-            startVertexId="421" startDirection="1.0 0.0 0.0" startLength="5"/>
-
+
         <TriangularFEMForceField name="FEM" youngModulus="60" poissonRatio="0.3" method="large" computePrincipalStress="true"/>
         <TriangularBendingSprings name="FEM-Bend" stiffness="300" damping="1.0" />
         <TriangleCollisionModel />
-
+
+        <TearingScenarioEngine name="TearingScenarioEngine" input_position="@Mo.position" showTearableTriangle="0" showFracturePath="1"
+            startVertexId="421" startDirection="1.0 0.0 0.0" startLength="3" />
+
         <Node >
             <OglModel name="Visual" color="red" />
             <IdentityMapping input="@.." output="@Visual" />

scenes/RegressionStateScenes.regression-tests

@@ -0,0 +1,12 @@
+# WARNING: 
+# REGRESSION_TEST DOES NOT SUPPORT DASHES ("-") IN SCENE NAMES.
+# USE UNDERSCORES ("_") INSTEAD.
+
+../regression/references
+
+### Demo scenes ###
+./TearingEngine/SquareTissue_01_gravity.scn 500 1e-4 1 1
+./TearingEngine/SquareTissue_02_pressureBorder.scn 500 1e-4 1 1
+./TearingEngine/SquareTissue_03_centralePressure.scn 500 1e-4 1 1
+./TearingEngine/SquareTissue_04_cornerPressure.scn 500 1e-4 1 1
+./TearingEngine/SquareTissue_05_circleHole_gravity.scn 500 1e-4 1 1

scenes/RegressionTopologyScenes.regression-tests

@@ -0,0 +1,13 @@
+# WARNING: 
+# REGRESSION_TEST DOES NOT SUPPORT DASHES ("-") IN SCENE NAMES.
+# USE UNDERSCORES ("_") INSTEAD.
+
+### References relative path ###
+../regression/references_topology
+
+### Topology scenes ###
+./TearingEngine/SquareTissue_01_gravity.scn 200 1e-4 1
+./TearingEngine/SquareTissue_02_pressureBorder.scn 200 1e-4 1
+./TearingEngine/SquareTissue_03_centralePressure.scn 200 1e-4 1
+./TearingEngine/SquareTissue_04_cornerPressure.scn 200 1e-4 1
+./TearingEngine/SquareTissue_05_circleHole_gravity.scn 200 1e-4 1

scenes/TearingEngine/SquareTissue_01_gravity.scn

@@ -43,19 +43,19 @@
         <TriangleSetGeometryAlgorithms name="GeomAlgo"   template="Vec3d" />
 
         <MechanicalObject name="Mo"/>
-        <DiagonalMass massDensity="10.0" />
+        <DiagonalMass massDensity="2.0" />
 
         <BoxROI name="FixedSide" box="-0.1 9.9 0.1  10.1 10.1 -0.1" drawBoxes="1" />
         <FixedConstraint name="FixedConstraint" indices="@FixedSide.indices" />
 
-        <TriangularFEMForceField name="FEM" youngModulus="60" poissonRatio="0.3" method="large" computePrincipalStress="1"/>
+        <TriangularFEMForceField name="FEM" youngModulus="300" poissonRatio="0.3" method="large" computePrincipalStress="1"/>
         <TriangularBendingSprings name="FEM-Bend" stiffness="300" />
         <PlaneForceField normal="0 1 0" d="-20" stiffness="100000" showPlane="1" showPlaneSize="20"/>
 
         <TriangleCollisionModel />
 
-        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="1.0" 
-            step="30" nbFractureMax="40" showFracturePath="0"/>
+        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="6.0" 
+            step="30" nbFractureMax="40" showFracturePath="1" fractureMaxLength="1.0"/>
 
         <Node >
             <OglModel name="Visual" color="red" />

scenes/TearingEngine/SquareTissue_01_gravity_interaction.scn

@@ -0,0 +1,65 @@
+<?xml version="1.0" ?>
+<!--Test case 1: Upper border is fixed and only heavy gravity is applied -->
+
+<Node name="root" dt="0.01" showBoundingTree="0" gravity="0 -10 0">
+	<Node name="RequiredPlugins">
+		<RequiredPlugin name="Sofa.Component.Collision.Detection.Algorithm"/> <!-- Needed to use components [BVHNarrowPhase, BruteForceBroadPhase, DefaultPipeline] -->
+		<RequiredPlugin name="Sofa.Component.Collision.Detection.Intersection"/> <!-- Needed to use components [MinProximityIntersection] -->
+		<RequiredPlugin name="Sofa.Component.Collision.Geometry"/> <!-- Needed to use components [TriangleCollisionModel] -->
+		<RequiredPlugin name="Sofa.Component.Collision.Response.Contact"/> <!-- Needed to use components [CollisionResponse] -->
+		<RequiredPlugin name="Sofa.Component.Constraint.Projective"/> <!-- Needed to use components [FixedConstraint] -->
+		<RequiredPlugin name="Sofa.Component.Engine.Select"/> <!-- Needed to use components [BoxROI] -->
+		<RequiredPlugin name="Sofa.Component.IO.Mesh"/> <!-- Needed to use components [MeshGmshLoader] -->
+		<RequiredPlugin name="Sofa.Component.LinearSolver.Iterative"/> <!-- Needed to use components [CGLinearSolver] -->
+		<RequiredPlugin name="Sofa.Component.Mapping.Linear"/> <!-- Needed to use components [IdentityMapping] -->
+		<RequiredPlugin name="Sofa.Component.Mass"/> <!-- Needed to use components [DiagonalMass] -->
+		<RequiredPlugin name="Sofa.Component.ODESolver.Backward"/> <!-- Needed to use components [EulerImplicitSolver] -->
+		<RequiredPlugin name="Sofa.Component.SceneUtility"/> <!-- Needed to use components [InfoComponent] -->
+		<RequiredPlugin name="Sofa.Component.SolidMechanics.FEM.Elastic"/> <!-- Needed to use components [TriangularFEMForceField] -->
+		<RequiredPlugin name="Sofa.Component.SolidMechanics.Spring"/> <!-- Needed to use components [TriangularBendingSprings] -->
+		<RequiredPlugin name="Sofa.Component.StateContainer"/> <!-- Needed to use components [MechanicalObject] -->
+		<RequiredPlugin name="Sofa.Component.Topology.Container.Dynamic"/> <!-- Needed to use components [TriangleSetGeometryAlgorithms, TriangleSetTopologyContainer, TriangleSetTopologyModifier] -->
+		<RequiredPlugin name="Sofa.Component.Visual"/> <!-- Needed to use components [VisualStyle] -->
+		<RequiredPlugin name="Sofa.GL.Component.Rendering3D"/> <!-- Needed to use components [OglModel] -->
+		<RequiredPlugin name="Tearing"/>
+	</Node>
+
+    <VisualStyle displayFlags="showVisual showBehaviorModels" />
+
+    <DefaultAnimationLoop />
+    <DefaultPipeline verbose="0" />
+    <BruteForceBroadPhase/>
+    <BVHNarrowPhase/>
+    <CollisionResponse response="PenalityContactForceField" />
+    <MinProximityIntersection name="Proximity" alarmDistance="0.8" contactDistance="0.5" />
+
+    <Node name="SquareGravity_FEM">
+        <EulerImplicitSolver name="cg_odesolver" printLog="false"  rayleighStiffness="0.1" rayleighMass="0.1" />
+        <CGLinearSolver iterations="25" name="linear solver" tolerance="1.0e-9" threshold="1.0e-9" />
+        <MeshGmshLoader name="meshLoader" filename="mesh/square3.msh" scale="10" createSubelements="true" />
+
+        <TriangleSetTopologyContainer  name="Container" src="@meshLoader" fileTopology="" tags=" " />
+        <TriangleSetTopologyModifier   name="Modifier" />
+        <TriangleSetGeometryAlgorithms name="GeomAlgo"   template="Vec3d" />
+
+        <MechanicalObject name="Mo"/>
+        <DiagonalMass massDensity="2.0" />
+
+        <BoxROI name="FixedSide" box="-0.1 9.9 0.1  10.1 10.1 -0.1" drawBoxes="1" />
+        <FixedConstraint name="FixedConstraint" indices="@FixedSide.indices" />
+
+        <TriangularFEMForceField name="FEM" youngModulus="300" poissonRatio="0.3" method="large" computePrincipalStress="1"/>
+        <TriangularBendingSprings name="FEM-Bend" stiffness="300" />
+        <PlaneForceField normal="0 1 0" d="-20" stiffness="100000" showPlane="1" showPlaneSize="20"/>
+
+        <TriangleCollisionModel />
+
+        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="12.0" 
+            step="30" nbFractureMax="40" showFracturePath="1" fractureMaxLength="1.5"/>
+
+        <Node >
+            <OglModel name="Visual" color="red" />
+            <IdentityMapping input="@.." output="@Visual" />
+        </Node>
+    </Node>   
+</Node>

scenes/TearingEngine/SquareTissue_02_pressureBorder.scn

@@ -50,11 +50,11 @@
         <FixedConstraint name="FixedConstraint" indices="@FixedSide.indices" />
 
         <BoxROI template="Vec3d" name="PulledSide" box="-0.1 0.1 0.1  10.1 -0.1 -0.1" drawBoxes="1"/>
-        <ConstantForceField name="CFF" indices="@PulledSide.indices" forces="0 -200 50" showArrowSize=".01" />
+        <ConstantForceField name="CFF" indices="@PulledSide.indices" forces="0 -40 10" showArrowSize=".01" />
 
-        <TriangularFEMForceField name="FEM" youngModulus="100" poissonRatio="0.3" method="large" computePrincipalStress="true" showStressVector="1"/>
-        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="0.3" 
-            step="20" nbFractureMax="40" showFracturePath="1"/>
+        <TriangularFEMForceField name="FEM" youngModulus="300" poissonRatio="0.3" method="large" computePrincipalStress="true" showStressVector="1"/>
+        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="6.0" 
+            step="30" nbFractureMax="40" showFracturePath="1" fractureMaxLength="1.0"/>
 
         <TriangularBendingSprings name="FEM-Bend" stiffness="300" damping="1.0" showSprings="0" />
         <PlaneForceField normal="0 1 0" d="-30" stiffness="100000" showPlane="1" showPlaneSize="20"/>

scenes/TearingEngine/SquareTissue_03_centralePressure.scn

@@ -53,13 +53,13 @@
 		<!--<BoxROI template="Vec3d" name="PulledSide" box="-0.1 0.1 0.1  10.1 -0.1 -0.1" drawBoxes="1"/>-->
 		<ConstantForceField name="CFF" indices="@PullMiddle.indices" forces="0 -300 0" showArrowSize=".01" />        
 
-		<TriangularFEMForceField name="FEM" youngModulus="100" poissonRatio="0.3" method="large" computePrincipalStress="true"/>
+		<TriangularFEMForceField name="FEM" youngModulus="300" poissonRatio="0.3" method="large" computePrincipalStress="true"/>
         <TriangularBendingSprings name="FEM-Bend" stiffness="300" damping="1.0" />
         <PlaneForceField normal="0 1 0" d="-30" stiffness="100000" showPlane="1" showPlaneSize="20"/>
 
         <TriangleCollisionModel />
-		<TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="0.1" 
-            step="20" nbFractureMax="40" showFracturePath="1"/>
+		<TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="6.0" 
+            step="30" nbFractureMax="40" showFracturePath="1" fractureMaxLength="1.0"/>
 
         <Node >
             <OglModel name="Visual" color="red" />

scenes/TearingEngine/SquareTissue_04_cornerPressure.scn

@@ -52,13 +52,13 @@
 		<BoxROI template="Vec3d" name="PullCorner" box="9.9 0.1 0.1  10.1 -0.1 -0.1" drawBoxes="1"/>
 		<ConstantForceField name="CFF" indices="@PullCorner.indices" forces="0 -160 0" showArrowSize=".02" />		
 
-		<TriangularFEMForceField name="FEM" youngModulus="60" poissonRatio="0.3" method="large" computePrincipalStress="true"/>
+		<TriangularFEMForceField name="FEM" youngModulus="300" poissonRatio="0.3" method="large" computePrincipalStress="true"/>
         <TriangularBendingSprings name="FEM-Bend" stiffness="300" damping="1.0" />
         <PlaneForceField normal="0 1 0" d="-30" stiffness="100000" showPlane="1" showPlaneSize="20"/>
 
         <TriangleCollisionModel />
-		<TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="0.2" 
-            step="20" nbFractureMax="40" showFracturePath="1"/>		
+		<TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="6.0" 
+            step="30" nbFractureMax="40" showFracturePath="1" fractureMaxLength="1.0"/>
 
         <Node >
             <OglModel name="Visual" color="red" />

scenes/TearingEngine/SquareTissue_05_circleHole_gravity.scn

@@ -1,7 +1,7 @@
 <?xml version="1.0" ?>
 <!--Test case 5: Square tissue mesh has a big circular hole in the middle. Upper border is fixed and only heavy gravity is applied -->
 
-<Node name="root" dt="0.05" showBoundingTree="0" gravity="0 -10 -1">
+<Node name="root" dt="0.05" showBoundingTree="0" gravity="0 -9 -1">
 	<Node name="RequiredPlugins">
 		<RequiredPlugin name="Sofa.Component.Collision.Detection.Algorithm"/> <!-- Needed to use components [BVHNarrowPhase, BruteForceBroadPhase, DefaultPipeline] -->
 		<RequiredPlugin name="Sofa.Component.Collision.Detection.Intersection"/> <!-- Needed to use components [MinProximityIntersection] -->
@@ -43,19 +43,19 @@
         <TriangleSetGeometryAlgorithms name="GeomAlgo"   template="Vec3d" />
 
         <MechanicalObject name="Mo"/>
-        <DiagonalMass massDensity="10.0" />
+        <DiagonalMass massDensity="1.0" />
 
         <BoxROI name="FixedSide" box="-0.1 9.9 0.1 10.1 10.1 -0.1" drawBoxes="1" />
         <FixedConstraint name="FixedConstraint" indices="@FixedSide.indices" />
 
-        <TriangularFEMForceField name="FEM" youngModulus="60" poissonRatio="0.3" method="large" computePrincipalStress="1"/>
+        <TriangularFEMForceField name="FEM" youngModulus="300" poissonRatio="0.3" method="large" computePrincipalStress="true"/>
         <TriangularBendingSprings name="FEM-Bend" stiffness="300" />
         <PlaneForceField normal="0 1 0" d="-30" stiffness="100000" showPlane="1" showPlaneSize="20"/>
 
         <TriangleCollisionModel />
 
-        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="1.0" 
-            step="30" nbFractureMax="40" showFracturePath="1"/>
+        <TearingEngine name="TearingEngine" input_position="@Mo.position" stressThreshold="6.0" 
+            step="30" nbFractureMax="40" showFracturePath="1" fractureMaxLength="1.0"/>
 
         <Node >
             <OglModel name="Visual" color="red" />